Apparatus for spirally winding strip metal

ABSTRACT

Apparatus for spirally winding strip metal comprising a pressure roll for urging the strip metal into a coil, feed rolls for feeding the strip material to the pressure roll and combining with the pressure roll to increase the radius of the strip material immediately preceding its application to the coil, and means for supporting the coil as it is wound and for maintaining the coil in contact with the pressure roll.

United States Patent 15] 3,698,223 Sagara 1 Oct. 17, 1972 APPARATUS FOR SPIRALLY WINDING [56] References Cited STRIP METAL UNITED STATES PATENTS [72] Inventor: H1deo Sagara, Hiroshima, Japan 1,935,092 8/1930 lverson ..72/148 [731 Asslgneei Mltslblsl" Jukogyo Kabush'kl 1,258,092 3/1918 Clark ..72/14s Kaisha, Ciyoda-ku, Tokyo, Japan 22 Filed; 1 19 9 Primary Examiner-Charles W. Lanham Assistant Examiner-R. M. Rogers [2]] Appl 888094 Att0rney-McGlew and Toren R lat dU.S.A at nD t e e pp a a 57 ABSTRACT [62] Division of Ser. No. 667,547, Sept. 13, 1967,

Pat No 3,528,161 Apparatus for spirally svmding strip metal comprising a pressure roll for urging the strip metal into a coil, [30] Foreign Applicafiml priority Data feed rolls for feeding the strip material to the pressure roll and combining with the pressure roll to increase P 271 I966 Japan "41/63593 the radius of the strip material immediately preceding its application to the coil, and means for supporting [52] US. Cl ..72/l46 the coil as it is wound and for maintaining the coil in [5 I I Illt. t t th pressure lL [58] Field of Search ..72/l48, 150, 152, 146

2 Claims, 5 Drawing Figures mm 11 Ian 7 7 3.698223 SHEET 1 0F 3 PATENTEDHBI man 3.698.223

SHEET 3 BF 3 IIIIIIII I I INVENTOI? l HIDEO SAGARA L n b 4 y ATTORNEY APPARATUS FOR SPIRALLY WINDING STRIP METAL CROSS-REFERENCE TO RELATED APPLICATION SUMMARY OF THE INVENTION In recent years there has been an increased use of high pressure processes in industry, particularly in the chemical industry, and these processes have required vessels and pipelines capable of withstanding high in ternal pressures at increased diameters. As the diameters of vessels and pipelines have increased, it has become increasingly more difficult to form these containers from metal plate. The equipment required to form the walls or shells of these vessels and pipelines from metal plate is quite large and expensive.

It has been considered advantageous to construct high pressure vessels and pipes by spirally winding a strip of high tensile steel approximately three to four mm in thickness and about 1,600 mm wide about a cylindrical core. After constructing these individual units, they can be joined together by welding to form a high pressure pipeline or by adding closure means to construct a high pressure vessel. Because relatively thin sheet steel can be easily obtained and wound be large diameters, it has provided a simple, safe and effective 30 high pressure tubular member which does not require any extensive and expensive forming means for shaping the walls of the member as would be the case if relatively thick steel plate were used.

Accordingly in the construction of chemical plants and other facilities which require high pressure vessels and/or pipes, spirally wound tubular members have become increasingly popular because of the inability to form the required tubular member from a single layer of steel plate because it is difficult to obtain the steel plate in such thicknesses and also because of the size and cost of the facilities required to form such plate into a tubular shape. Another advantage of spirally wound tubular members is that they require no longitudinal seam welding as compared to plate members and therefore the problems involved in heat treating the longitudinal welds is avoided. Because of the problems involved in forming tubular members of thick steel plate, the use of spirally wound multi-layer tubular 5 members has become increasingly popular.

In the manufacture of spirally wound multi-layer tubular members having a considerable length and thickness, if relatively thin sheet metal is used, it must be wound a great number of times to provide the desired thickness and, if necessary, the tubular members must then be butt-welded if a member of increased length is required. When the sheet metal of a thickness of 4 mm or less is used, padding must be applied to the ends of the multi-layer tubular members before they can be welded together. Because of this characteristic, the welding time needed for joining multi-layer tubular members is considerably longer than is required for spirally winding the members, and, as can be appreciated, the time required to weld the joining pipes will be in inverse proportion to the thickness of the sheet steel employed in winding the pipe. Moreover, when the sheet metal being wound is relatively thin,

such as on the order of the size mentioned above, the thermal conductivity of the member is poor because of the great number of interfaces involved. Due to the poor heat conductivity characteristics of thin sheet metal, the heat treatment of the welded points of the members is a very slow process since the tubular members must be heated uniformly at a rather slow speed to avoid the development of any excess internal stress in the spirally wound layers. Further, in heat treating tubular members formed of thin sheet metal, a complete facility must be installed and the operation takes a considerable time during which the surface of the multilayer sheet member becomes oxidized.

The disadvantages just described for thin sheet metal vary directly with the length and, more particularly, with the thickness of the tubular member formed.

These disadvantages which stem from the use of thin sheet metal in spirally wound multi-layer tubular mem- 0 bers can be reduced or eliminated when the sheet metal is increased above 5 mm up to a thickness of about 12 mm. In practice, however, as the thickness of the sheet or plate metal increases, it becomes more difficult to wind or coil it in a multiple number of layers, particularly when it is in a cold condition.

Moreover, it is difficult to obtain from a producer coils of plate metal having a thickness on the order of 12 mm which has been descaled, smoothed, and heattreated with both edges trimmed to a desired width. For purposes of the invention, the sheet or plate metal must be in the form of a long strip so that it can be wound continuously about a tubular core forming multi-layer member, and when strip material is mentioned herein, it refers to a continuous length of sheet or plate material and is not limited to any specific ranges of thickness. When sheets of steel plate, which have'been treated and shaped as mentioned above, are obtained and welded together in the form of a strip, the bending strength and elasticity of the strip is quite high (for example, in the case of a strip of steel having a thickness of 12 mm, the winding force is between 16 to 64 times as great compared with that required for winding similar steel material which is only 3 to 4 mm in thickness. As a result, when such material is wound, gaps or open spaces are apt to develop between the layers and as the gaps increase in size, excess tensile stress develops about the outer peripheral surface of each layer. If the layers of the tubular member are 0 stressed in the winding process, its ability to withstand tensile stress when exposed to internal pressure will be reduced.

The present invention provides apparatus of spirally winding a strip of relatively thick steel material in which the disadvantages mentioned above are avoided. In the present invention, the strip of steel material is initially wound in a coil of given curved configuration having a radius approximately equal to the radius of the tubular member to be formed. In spirally winding the tubular member, the steel material is unwound from the supply coil and is pressed forcibly at the winding point or winding station by means of a pressure roller. In the course of winding the steel material onto the tubular member, if it is necessary to do so, the edges of the strip can be displaced laterally by the force exerted by the pressure roller whereby the edges of the strip, in successive layers, can be properly aligned.

The present invention is based on the use of a strip of steel having a thickness greater than 5 mm and with its leading and trailing edges which contact the core member and the cover plate of the tubular member respectively fashioned in a tapered wedge-shaped configuration to properly contact these respective members and avoid the development of gaps during the winding operation. When the strip has been completely wound on the core and its outer or trailing edge has been locked in place by means of a cover member, a plurality of bores or openings or holes may be formed through the cover member and the multiple layers terminating at the inner surface of the inner layer. If individual tubular members, constructed according to the present invention, are to be welded together into a composite member for use as a pipe or vessel, the openings through the layers of the tubular member are used for circulating an inert gas through the layers during heat treatment of the welded joints. The circulation of inert gas replaces the air trapped between the layers and prevents oxidation of the contacting surfaces of the layers. Additionally, measuring instruments may be inserted into the openings to determine and maintain the proper temperatures in the various layers.

One of the primary characteristics of the present invention is the use of steel strip which is supplied in a coil having curved configuration similar to that in which the tubular member is to to formed. The coiled shape of the strip permits it to be closely wound about the core requiring a relatively small amount of pressure at the winding station. Due to the curved configuration of the steel strip employed and the manner in which it is fed to the winding station, the outer surface of the steel material is slightly shortened and the inner surface is slightly elongated as it is wound onto the tubular member. In this way the steel strip can be easily wound in the same fashion as if tensile stress were applied to a flat strip of material.

In the event there is any displacement of the edge of the strip being applied, as compared to the edge already wound on the core, it is possible to exert an increased force on one half of the roller at the winding station and thereby laterally displace the edge as it is wound. In such an arrangement the portion of steel strip receiving the higher pressure will be wound by shorter length and moved into proper alignment with the edge of the underlying layer.

During the winding operation to prevent any slipping between the layers of steel strip and avoid the formation of gaps between adjacent layers, the force provided by the pressure roller is sufficient to develop a frictional force on the steel to avoid any slippage, or, as an alternative, the end edges of the layers may be tackwelded as each layer passes the winding station.

In spirally wound tubular members using relatively thick steel strip according to the present invention, the distance between the abutting surfaces of the layers is increased over that where thinner strip was used. When a plurality of these tubular members are joined end-toend, a larger diameter welding rod and a continuous welding operation may be employed which provides a considerable advantage over the prior method. During the welding operation when the individual layers are heated and expand, the air between adjacent layers can be discharged through the openings formed in the tubular members. When alloy steel is utilized as the strip material, the inert gases can be introduced between the layers for heat treating the welded joints. Moreover, the temperature of the individual layers can be measured by inserting an instrument into the radial openings in the tubular member to maintain a proper temperature range during the heat treating process. Further, because of the increased thickness of the steel material used, the thermal conductivity of the tubular member is improved and as a result the time for heat treating is decreased. Additionally, the inert gases introduced in the openings of the tubular member displaces any air between the layers and reduces the possibility of oxidation of the abutting surfaces of the layers.

Accordingly, the primary object of the present invention is to provide apparatus to form a high pressure tubular member by spirally winding a relatively thick metal strip of steel to form the member.

Another object of the invention is to employ a metal strip having a curved configuration or coiled to a radius approximating that of the tubular member prior to its use in forming the member.

Still, another object of the invention is to form a spirally wound tubular member in which the overlapping layers are in close engagement and the layers are locked against sliding or displacement after the member has been wound.

A further object of the invention is to increase the radius of curvature of the metal strip immediately preceding the winding station.

Another object of the invention is to provide the metal strip with a tapered leading and trailing edge as it is fed onto the tubular member whereby the strip forms a properly cylindrical configuration.

A further object of the invention is to produce spirally wound tubular members made of metal strip of an increased thickness as compared to that previously used whereby the cost of forming the members is reduced and the apparatus required for forming the member is also kept to a minimum.

The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this specification. For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had to the accompanying drawings and descriptive matter in which there is illustrated and described a preferred embodiment of the invention.

DESCRIPTION OF THE DRAWINGS In the drawings:

FIG. 1 is a somewhat schematic illustration of the apparatus employed in forming multi-layer tubular members in accordance with the present invention;

FIG. 2 is a transverse view of a tubular member formed in accordance with the present invention; and

FIG. 3 is a longitudinal view, partly in section, of a composite tubular member formed by a number of tubular members illustrated in FIG. 2;

FIG. 4 is a perspective view generally corresponding to FIG. 1; and

FIG. 5 is a side view, partly in section, of the apparatus illustrated in FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION In FIG. 1 a tubular member is shown in the process of being formed by a metal strip 2, such as steel, wound about a core member 1. The metal strip is 12 mm in thickness and 1,800 mm in width with a tensile strength of 60 kg per mm and is supplied in a coil having a radius of curvature approximating that of the tubular member to be formed (the metal strip supply coil is not shown in FIG. 1). From the supply coil the metal strip 2 passes between a pair of rollers 4 and is fed to a pressure roller 4 which forms the winding station A, that is the position at which the metal strip begins to be coiled onto the core member 1. The pres sure roller 4 exerts an inwardly directed pressure against the metal strip coiled onto the tubular member as indicated by the arrow. Since the metal strip 2 is supplied in a curved configuration when it is fed to the winding station A, a relatively small application of pressure by the roller 4 is required to wrap the material about the core member 1. At the opposite side of the tubular member 10 from the winding station A, a pair of rollers 4" are located for rotating the tubular member as it is being formed and for keeping the member in contact with the pressure roller 4.

The position of the rollers 4' is adjustable so that the metal strip 2, as it is fed toward the winding station A, can be given a radius of curvature r slightly greater than the radius R it is to assume on the tubular member. If, for example, the radius R of the metal strip on the tubular member 10 equals 2,000 mm, then the radius r equals about 2,180 mm as it is introduced to the winding station A. The increased curvature imparted to the metal strip causes the outer surface 2 of the steel material to assume a slightly fattened configuration immediately preceding the winding station A and the inner surface 2" at the same location becomes slightly elongated in the amount of about 0.25/1000 cm/cm. In other words, as the steel material 2 is fed onto the tubular member at winding station A, its outer surface 2' is shorter relative to its inner surface 2" by an amount of 0.50/1000 cm/cm. If it is assumed that the modulus of elasticity of the steel material is E 2 X l0 kg/cm then the tensile stress is E X 0.25/1000 and equals 500 kg/cm at the inner surface of the metal strip at its point of application to the tubular member, winding station Any tendency for one layer to slip with respect to the other at the winding station A is prevented by the frictional force imparted by the pressure roller 4, which exerts a force of about 300 tons. Additionally, slipping can also be prevented by tack welding the layers together after they pass the winding station A. After the metal strip 2 passes the winding station A and forms a layer 3 on the tubular member 10, a stress of 500 kg/cm is developed in the entire section of the strip as it assumes the radius (R) of 2,000 mm.

If during the winding process the edge of the metal strip delivered to the winding station A should extend beyond the edge of the layers 3 already wrapped around the core member 1, the magnitude of the force exerted by the roller 4 can be increased against the extending edge portion so that it will be wound by shorter length and will move in the direction of the edge of the layer which it overlies. In this way it is possible to maintain the edges of the metal strip in alignment with the edges already positioned on the core member during the winding operation.

In FIG. 4, arrows P and P, indicate the pressing forces applied at the opposite ends of roller 4 for adjustably applyingpressure across the width of strip 2 as it is applied to tubular member 10 at winding station A. The pressures P, and P may be maintained at the same value or, as necessary for displacing strip 2 laterally relative to the underlying strip, the pressure at one edge of strip 2 can be varied relative to the pressure at the opposite edge thereof, for displacing strip 2 laterally so that the edges of the overlying strips are in alignment.

As indicated in FIG. 5, pressing forces P and P are exerted on bearings 13 and 14, respectively, on opposite ends of roller 4, by respective hydraulic actuators l1 and 12. As also illustrated in FIG. 5, the ends of one roller 4" are supported in bearings 15 and 16, and the other roller 4" is supported in a similar manner. The ends of inside guide roller 4', which is inside relative to the location of metal strip 2 and the tubular member, are supported in bearings 17 and 18, and the outside guide roller 4' is supported in a similar manner. The bearings 17 and 18, as well as the bearings for the outside guide roller, are fixed on respective slide shoes which are movable horizontally, as by means of a suitable hydraulic actuator, along respective guide plates.

Thus, the pressing force of the pressure roller 4 can be varied by means of the hydraulic actuators 11 and 12 and, as a result, the pressing force can be adjustably varied along the axis of roller 4. Additionally, the positions of the guide rollers 4' can be varied by adjustment of their respective bearings along the associated slides, as through the medium of a hydraulic actuator.

As can be noted-in FIGS. 1 and 2, the leading edge 2a of the metal strip 2, applied to the core member 1 has a tapered wedge-like configuration so that it properly overlies the core member and does not cause any gap between the core member and the overlapping metal strip. For the same reason, the trailing edge 2b of the strip is provided with a similar tapered wedge-like con figuration where it contacts the cover members 5, as shown in FIG. 2. The cover members 5 have a semicylindrical shape with an inside diameter substantially equal to the outside diameter of outer layer 3 wound on the core member 1 and are joined by welds 6.

If the tubular member 10 is to be secured to another similar member in forming a composite pipe or vessel or to a closure member forming the end of a container or vessel, it is provided with a number of radially arranged openings 7 which extend from the outer surface of the cover plates 5 interiorly to the inner surface of the innermost layer 3 of the metal strip 2. The purposes of the openings 7 will be explained hereafter.

The tubular members 10 may be secured together by welding to form an extended pipe member as shown in FIG. 3.

In the spirally wound tubular member 10, compared to members having a layer thickness of 3 mm, the layer thickness of 12 mm reduces by one quarter the total number of layers and total length of the strip metal utilized. Because of the increased thickness and the reduced number of interfaces, the thermal conductivity in the radial direction of the layers is better than in a tubular member having a greater number of thinner layers. When a number of tubular members 10 are joined together to form a pipe line, no padding is required at the end faces of the layers as was necessary in the pipes using a much thinner layer and the thicker layers can be joined together in a continuous automatic welding operation.

After individual tubular members 10 are welded together, as shown in FIG. 3, the welded joint is heat treated, especially where alloy steels are employed, by circulating an inert gas through the openings 7. During the heat treatment operation, temperature measuring instruments can be inserted into the openings 7 so that the temperature distribution in the various layers can be checked and the temperature suitably adjusted, if necessary. Additionally, with the circulation of inert gas through the layers between the tubular member any air which is present is displaced and the possibility of oxidation of the abutting layer surfaces is eliminated. After the heat treatment operation is complete, the openings 7 may be sealed in any suitable manner.

Though the present invention has been described as a applied to manufacturing a spirally wound tubular member, it is also possible to employ it in forming the metal strip into a supply coil from which it is unwound in forming the tubular member. In accordance with the present invention, steel strip having a thickness of 12 mm can then be coiled in the cold rolling procedure using the general process as indicated in FIG. 1.

Accordingly, a coil of steel strip can be obtained for use in forming tubular members or for other purposes which has been descaled, smoothed, and properly trimmed to size as required.

When the steel material is coiled in this fashion prior to being wound on the tubular member, the end of the steel material will not have a tendency to spring back from its wound position, particularly if in its supply coil it had a radius approximating that of the radius of curvature given it in the winding operation of the tubular member. When using such coiled steel strip, it is not necessary to provide an increased pressure at the winding station or to otherwise tack weld or attach the strip to the core member at the beginning of the winding step. As indicated previously, as the strip is fed to the winding station, the rollers 4' in conjunction with the roll 4 increase the radius of the steel material and provide it with a slightly flattened configuration at the point of application to the winding station A.

By employing the apparatus of the present invention, a tubular member can be wound from a relatively wide and thick section of metal in a simple, efficient and economical manner. The strip can be prepared by a producer including the required steps of scaling, smoothing, trimming, etc. and can be properly wound to the desired radius of curvature for shipment and use in forming a multi-layer tubular member. As an alternative, the coil may be directly heat treated for the purposes of tempering or normalizing it and shipped in that fashion.

As compared to the thin metal sections previously used, it is possible, by employing a metal strip of 12 mm in thickness, to obtain an improved thermal conductivity, and the rigidity of the strip due to its thickness is such that it will not be deformed in heat treatment as is more likely to be the case where thin sections are utilized. Moreover, it is easier to normalize the thicker steel section to increase its yield point, and such normalization can be effected while the material is in the form of a coil. When spirally wound metal strip is used in manufacturing tubular members as described above, the bending operation normally employed before the winding operation is eliminated. In other words, if metal plate having a higher yield point and an uncurved configuration is coiled or spirally wound on a core member, extensive facilities and considerable power are required to achieve the bending forces and by utilizing the present invention, such facilities are not required.

While a specific embodiment of the invention has been shown and described in detail to illustrate the application of the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles.

lclaim:

1. Apparatus for spirally winding strip metal to form a multi-layer tubular body comprising, in combination, a pressure roll engaging the strip metal and forcing the strip metal to coil to form successive contiguous spiral layers of the tubular body; means feeding the strip metal to said pressure roll; means supporting the coiled strip metal in a zone opposite said pressure roll and resisting movement of the coiled strip metal way from said pressure roll; bearings supporting opposite ends of said pressure roll; and respective pressure exerting means engaged with each bearing, said pressure exerting means being independently adjustable whereby the pressure exerted on the strip metal can be varied axially of said pressure roll and laterally of said strip metal.

2. Apparatus as set forth in claim 1, in which said means feeding the strip metal comprises a pair of feed rollers engaging and gripping respective opposite surfaces of the strip metal in advance of said pressure roll; said feed rollers being adjustable as to position and acting conjointly with said pressure roll to increase the radius of the strip metal prior to winding thereof into a multi-layer coil. 

1. Apparatus for spirally winding strip metal to form a multilayer tubular body comprising, in combination, a pressure roll engaging the strip metal and forcing the strip metal to coil to form successive contiguous spiral layers of the tubular body; means feeding the strip metal to said pressure roll; means supporting the coiled strip metal in a zone opposite said pressure roll and resisting movement of the coiled strip metal way from said pressure roll; bearings supporting opposite ends of said pressure roll; and respective pressure exerting means engaged with each bearing, said pressure exerting means being independently adjustable whereby the pressure exerted on the strip metal can be varied axially of said pressure roll and laterally of said strip metal.
 2. Apparatus as set forth in claim 1, in which said means feeding the strip metal comprises a pair of feed rollers engaging and gripping respective opposite surfaces of the strip metal in advance of said pressure roll; said feed rollers being adjustable as to position and acting conjointly with said pressure roll to increase the radius of the strip metal prior to winding thereof into a multi-layer coil. 